Epidemiologic data of renal diseases from a single unit in China: analysis based on 13,519 renal biopsies

Prevalence and prognosis of malignancy in THSD7A-associated membranous nephropathy: a systematic literature review and clinical case study

BACKGROUND

This study aims to investigate the incidence and prognosis of malignancy in individuals with thrombospondin type-1 domain-containing 7A (THSD7A)-associated membranous nephropathy (MN).

METHODS

First, we performed a systematic literature review of prevalence of malignancy in THSD7A-associated MN. Then, we conducted a retrospective analysis of 454 patients diagnosed with MN through renal biopsy at our hospital between January 2016 and December 2020. We assessed the presence of serum anti-THSD7A antibodies and performed immunohistochemical staining of renal tissue for THSD7A. Subsequently, we followed patients with THSD7A-associated MN for a minimum of 3-5 years, collecting their clinical, pathological characteristics, and prognosis. Additionally, we conducted a literature review on patients with THSD7A-associated MN in conjunction with malignancy.

RESULTS

We identified a total of nine articles containing comprehensive data on THSD7A-associated MN and malignancy. Among 235 patients with THSD7A-positive MN, 36 individuals had concurrent malignancies, resulting in a malignancy prevalence of 13.3% (95% CI: 8.9-17.7%). In our center, we followed up with 15 patients diagnosed with THSD7A-associated MN and observed three cases of concomitant tumors: two cases of lung adenocarcinoma and one case of small cell lung cancer with multiple metastases. The prevalence of malignancy in our cohort was 20%. Notably, we detected positive THSD7A staining in both renal and lung cancer tissues in one patient with small cell lung cancer.

CONCLUSIONS

Patients with THSD7A-associated MN should undergo vigilant follow-up assessments, with a particular focus on actively seeking potential tumorigenic lesions to prevent misdiagnosis or oversight.

Changes in the spectrum of biopsy-proven renal diseases over 11 years: a single-center study in China

BACKGROUND

There have been some shifts in the frequency and distribution of biopsy-proven renal diseases in China over recent years. The aim of the study was to investigate the changing spectrum of renal diseases from the view of kidney biopsy data in a single center of China.

METHODS AND RESULTS

A total of 10,996 cases of native renal biopsies from patients aged ≥15 years old in Huashan Hospital, Fudan University, between 2008 and 2018 were analyzed retrospectively. The results showed that primary glomerular nephropathy (PGN) remained the most common biopsy-proven renal disease (69.42% of total), with IgA nephropathy (IgAN) accounting for 44.40% of PGN, membranous nephropathy (MN) for 28.55%, minimal change disease (MCD) for 13.26% and focal segmental glomerulosclerosis (FSGS) for 8.00%. During the study period, the proportion of MN in PGN appeared an increasing tendency, while that of IgAN and MCD remained stable and that of FSGS showed a decline. Secondary glomerular nephropathy (SGN) constituted 21.54% of total cases, among which the leading two diseases were lupus nephritis (LN) and Henoch-Schonlein purpura nephritis (HSN) which accounted for 41.08% and 19.11% respectively.

CONCLUSIONS

The 11-year retrospective study revealed that PGN was the predominant histologic diagnosis among patients undergoing renal biopsy and the most frequent type of PGN remained to be IgAN, followed by MN which increased dramatically.

Prevalence and immunopathologic characteristics of seropositive and seronegative hepatitis B virus-associated membranous nephropathy: a retrospective study of 420 biopsy-proven cases

BACKGROUND

This retrospective study aims to investigate the prevalence and immunopathologic characteristics of seropositive and seronegative hepatitis B virus-associated membranous nephropathy (HBV-MN).

METHODS

Clinicopathologic and serologic records of 420 patients with histologically confirmed HBV-MN between January 2014 and July 2021 were examined to determine the prevalence of seropositive and seronegative HBV-MN. Serum anti-PLA2R antibody testing was conducted on 280 patients with HBV-associated membranous nephropathy (HBV-MN) from August 2018 to July 2021. Immunopathologic characteristics of HBV-MN patients and anti-PLA2R antibody positivity were analyzed.

RESULTS

Among 420 pathologically confirmed HBV-MN patients, 230 (54.8%) were seropositive for HBV. The seropositive group exhibited higher blood creatinine values and incidence of liver function abnormalities than the seronegative group (p < .05). Serum anti-PLA2R antibody testing on 280 HBV-MN patients revealed a total positive rate of 44.6%, with the seronegative group showing a significantly higher rate (62.6%) compared to the seropositive group (32.1%) (p < .01). The anti-PLA2R antibody-positive group displayed higher levels of urine protein (p < .05), serum cholesterol (p < .01), and IgG4 subtypes (p < .05) compared to the negative group. Additionally, the positive group had significantly lower levels of serum albumin and IgG than the negative group (p < .01).

CONCLUSIONS

This comprehensive study reveals a significantly higher prevalence of seronegative HBV-MN than previously thought. The blood creatinine values and incidence of liver function abnormalities was higher in the serology-positive group than in the serology-negative group. Notably, the seronegative group displayed a higher positive rate of anti-PLA2R antibodies compared to the seropositive group, indicating distinctive clinical and immunopathologic features.

Exploring PLA2R and HLA in membranous nephropathy: A narrative review of pathogenic mechanisms and emerging therapeutic potentials

Membranous Nephropathy (MN), a non-inflammatory autoimmune glomerulopathy, is a prominent cause of nephrotic syndrome, predominantly affecting Caucasian adults. It is characterized by significant thickening of the glomerular basement membrane, a direct result of immune complex deposition. Fundamental to its pathogenesis are the Phospholipase A2 receptor (PLA2R) and Human Leukocyte Antigens (HLA), which play crucial and interconnected roles. Specifically, PLA2R serves as the primary antigen, while HLA molecules facilitate MN-specific immune responses, thereby providing key insights into the disease's etiology. This study critically examines the roles of PLA2R and HLA in MN, with a particular focus on the antigenic epitopes of PLA2R. Given MN's complex nature, personalized therapeutic interventions are essential. Accordingly, targeting immunogenic epitopes has emerged as a transformative approach, aimed at modulating specific immune responses without disrupting overall immune function. Numerous studies and clinical trials have been advancing the application of these epitopes in therapeutic strategies. Nevertheless, challenges such as identifying effective epitopes, enhancing epitope-specific responses, and optimizing therapeutic dosing remain. This narrative review addresses these challenges in depth, offering a comprehensive insight into the pathology and emerging treatment strategies for MN.

Tubulointerstitial nephropathy is the predominant finding in men in a review of more than 3000 renal biopsies over a 10-year period from Sri Lanka

BACKGROUND

Chronic kidney disease (CKD) is a significant clinical challenge in Sri Lanka. The present study presents histopathological diagnoses from native renal biopsies in Kandy District, 2011-2020.

METHODS

Reports of 5,014 renal biopsies principally performed at Kandy Teaching Hospital over 2011-2020 were reviewed. After exclusions for post-kidney transplant biopsies (1,572) and those without evident pathology (347), 3,095 biopsies were included. The predominant histopathological entities were grouped and categorised according to diagnosis and stratified by age and sex.

RESULTS

The main histopathological entities (all biopsies) were tubulointerstitial nephropathy (TIN) 25% (n = 760), glomerulonephritis (GN) 15% (467), lupus nephropathy 14% (429), focal segmental glomerular sclerosis (FSGS) 10% (297), and IgA nephropathy (IgAN) 8% (242). For adult women ≥ 15 years, the main histopathological entities were lupus nephropathy 24% (325), TIN 17% (228), and GN 16% (217). For adult men ≥ 15 years, the main histopathological entities were TIN 34% (449), GN 14% (180), and IgAN 10% (125). The proportion of TIN in the present study was higher than international studies of a similar size.

CONCLUSION

This is the largest study of renal biopsies reported from Sri Lanka to date. TIN was the most common diagnosis in adults ≥ 15 years at 25%. Notable sex differences showed TIN was the most common histopathology in men (34%) but not in women (17%). No previously published similar study of this size has found TIN as the predominant diagnosis amongst renal biopsies in men. Further research is required into the possible causes of these observations in Sri Lanka.

CLINICAL TRIAL NUMBER

Not applicable.

State-of-Art Therapeutics in IgA Nephropathy

Immunoglobulin-A nephropathy (IgAN) is the most common primary glomerulonephritis in the world, with up to 40% of patients progressing to end-stage kidney disease (ESKD) within 30 years of diagnosis. IgAN is characterized by elevated serum levels of galactose-deficient IgA1 (Gd-IgA1), which leads to immune complex formation and deposition in the glomerular mesangium, causing kidney injury. A diverse disease course and the long-term follow-up required for clinically relevant endpoints (e.g., ESKD) have been barriers to the development of novel therapies in IgAN. Disease management has focused on supportive care with inhibitors of the renin-angiotensin system and, more recently, sodium-glucose transporter inhibitors to control proteinuria. The recent acceptance of proteinuria as a surrogate endpoint by regulatory bodies and a better understanding of disease pathology have helped to initiate the development of several novel treatments. Subsequently, a targeted-release formulation of budesonide and a dual endothelin/angiotensin inhibitor (sparsentan) have received accelerated approval for patients with IgAN. However, additional therapies are needed to target the different pathogenic mechanisms and individualize patient care. Several compounds currently under investigation target various effectors of pathology. There are promising clinical results from emerging compounds that target the generation of Gd-IgA1 by B cells, including inhibitors of A PRoliferation-Inducing Ligand (APRIL) and dual inhibitors of APRIL and B-cell activating factor (BAFF). Other investigational therapies target the complement cascade by inhibiting proteins of the lectin or alternative pathways. As the therapeutic landscape evolves, it will be important to revise treatment guidelines and develop updated standards of care.

Hospital Healthcare Resource Utilization and Associated Hospital Costs of Patients With Lupus Nephritis in China: A National Administrative Claim Database Study

OBJECTIVES

Assess hospital healthcare resource utilization (HCRU) and associated hospital costs of patients with lupus nephritis (LN) in China and compare these outcomes with a systemic lupus erythematosus (SLE) cohort (SLE with/without LN) as well as exploring the effect of end-stage kidney disease (ESKD).

METHODS

This retrospective administrative claims-based analysis identified patients with SLE and SLE with LN from China using diagnosis codes and keywords. Patients with LN were subcategorized by presence of ESKD. Outcomes included all-cause and disease-specific HCRU (defined as healthcare visits including inpatient and outpatient visits) and medical costs (in 2022 US dollars).

RESULTS

In total, 3645 patients with SLE were included, of whom 404 (11%) had LN. Among those with LN, 142 (35%) had ESKD. Median (interquartile range) all-cause healthcare visits per patient per month (PPPM) was significantly greater for patients with LN (2.08 [4.01]) vs SLE (0.92 [1.64]; P < .0001). Patients with LN and ESKD (3.00 [4.18]) had numerically more all-cause healthcare visits PPPM compared with LN patients without ESKD (1.50 [3.45]). Median all-cause costs PPPM were significantly greater among patients with LN ($287.46 [477.15]) vs SLE ($113.09 [267.39]; P < .0001) and numerically higher for patients with LN and ESKD ($466.29 [958.90]) vs LN without ESKD ($223.50 [319.56]).

CONCLUSIONS

Chinese patients with LN had greater HCRU and hospital healthcare costs compared with the general SLE cohort. This burden was higher for those with ESKD. These data highlight the substantial HCRU among patients with LN in China, especially those with ESKD, suggesting the need for early diagnosis and timely management of LN to mitigate the economic burden.

Lupus Nephritis from Pathogenesis to New Therapies: An Update

Lupus Nephritis (LN) still represents one of the most severe complications of Systemic Lupus Erythematosus (SLE) and a major risk factor for morbidity and mortality. However, over the last few years, several studies have paved the way for a deeper understanding of its pathogenetic mechanisms and more targeted treatments. This review aims to provide a comprehensive update on progress on several key aspects in this setting: pathogenetic mechanisms of LN, including new insight into the role of autoantibodies, complement, vitamin D deficiency, and interaction between infiltrating immune cells and kidney resident ones; the evolving role of renal biopsy and biomarkers, which may integrate information from renal histology; newly approved drugs such as voclosporin (VOC) and belimumab (BEL), allowing a more articulate strategy for induction therapy, and other promising phase III-immunosuppressive (IS) agents in the pipeline. Several adjunctive treatments aimed at reducing cardiovascular risk and progression of chronic renal damage, such as antiproteinuric agents, represent an important complement to IS therapy. Furthermore, non-pharmacological measures concerning general lifestyle and diet should also be adopted when managing LN. Integrating these therapeutic areas requires an effort towards a holistic and multidisciplinary approach. At the same time, the availability of an increasingly wider armamentarium may translate into improvements in patient's renal outcomes over the next decades.

Are children with IgA nephropathy different from adult patients?

BACKGROUND

Previously, several studies have indicated that pediatric IgA nephropathy (IgAN) might be different from adult IgAN, and treatment strategies might be also different between pediatric IgAN and adult IgAN.

METHODS

We analyzed two prospective cohorts established by pediatric and adult nephrologists, respectively. A comprehensive analysis was performed investigating the difference in clinical and pathological characteristics, treatment, and prognosis between children and adults with IgAN.

RESULTS

A total of 1015 children and 1911 adults with IgAN were eligible for analysis. More frequent gross hematuria (88% vs. 20%, p < 0.0001) and higher proteinuria (1.8 vs. 1.3 g/d, p < 0.0001) were seen in children compared to adults. In comparison, the estimated glomerular filtration rate (eGFR) was lower in adults (80.4 vs. 163 ml/min/1.73 m2, p < 0.0001). Hypertension was more prevalent in adult patients. Pathologically, a higher proportion of M1 was revealed (62% vs. 39%, p < 0.0001) in children than in adults. S1 (62% vs. 28%, p < 0.0001) and T1-2 (34% vs. 8%, p < 0.0001) were more frequent in adults. Adjusted by proteinuria, eGFR, and hypertension, children were more likely to be treated with glucocorticoids than adults (87% vs. 45%, p < 0.0001). After propensity score matching, in IgAN with proteinuria > 1 g/d, children treated with steroids were 1.87 (95% CI 1.16-3.02, p = 0.01) times more likely to reach complete remission of proteinuria compared with adults treated with steroids.

CONCLUSIONS

Children present significantly differently from adults with IgAN in clinical and pathological manifestations and disease progression. Steroid response might be better in children.

Management and Clinical Outcomes of Membranous Nephropathy, IgA Nephropathy, and Minimal Change Disease Two Years Post-Kidney Biopsy

INTRODUCTION

This study evaluated the phenotypic and pathology characteristics of patients undergoing kidney biopsy at a single center, while also determining the frequency and factors associated with clinical outcomes.

METHODS

The incidence and distribution of biopsy-proven kidney diseases in 2000-2019 were surveyed. Consecutive individuals diagnosed with membranous nephropathy (MN), immunoglobulin A nephropathy (IgAN), and minimal change disease (MCD) between August 2015 and December 2019 were enrolled in the prospective 2-year follow-up study. Outcomes included remission of proteinuria and kidney disease progression events. Multivariable-adjusted Cox proportional hazards model was applied.

RESULTS

4,550 kidney biopsies were performed in 2000-2019, showing a noticeable increase in the proportion of MN. 426 patients were enrolled in the follow-up cohort. 346 (81.2%) achieved remission of proteinuria, 39 (9.2%) suffered kidney disease progression and 51.3% of them were diagnosed with IgAN. Kidney pathological diagnosis (MN vs. MCD: hazard ratio [HR], 0.42; 95% confidence interval [95% CI], 0.31-0.57; IgAN vs. MCD: 0.58; 0.39-0.85), levels of 24-h urine protein at biopsy (1.04; 1.00-1.08) and presence of nodular mesangial sclerosis (0.70; 0.49-0.99) were significantly correlated with remission of proteinuria after adjusting for baseline variables. 24-h urine protein levels at biopsy (1.14; 1.04-1.25) and the presence of crescents (2.30; 1.06-4.95) were the independent risk factors for kidney disease progression events after adjusting for baseline variables.

CONCLUSION

The increasing frequency of MN has been affirmed over the past 2 decades. The therapeutic status, clinical outcomes, and factors influencing these outcomes were presented in this single-center study for the three primary glomerular diseases.

Blockade of Notch1 Signaling Alleviated Podocyte Injury in Lupus Nephritis Via Inhibition of NLRP3 Inflammasome Activation

To explore the role of Notch1 pathway in the pathogenesis of podocyte injury, and to provide novel strategy for podocyte repair in lupus nephritis (LN). Bioinformatics analysis and immunofluorescence assay were applied to determine the expression and localization of Notch1 intracellular domain1 (NICD1) in kidneys of LN patients and MRL/lpr mice. The stable podocyte injury model in vitro was established by puromycin aminonucleoside (PAN) treatment. Expression of inflammasome activation related gene was detected by qPCR. The podocytes with PAN treatment were cultured with or without N-S-phenyl-glycine-t-butylester (DAPT), an inhibitor of Notch1 pathway. NICD1, Wilm'stumor1 (WT1), nucleotide-binding oligomerization domain-like receptors 3 (NLRP3), and absent in melanoma-like receptors 2 (AIM2) were detected by western blot. In vivo, MRL/lpr mice were administrated with DAPT or vehicle. The LN symptoms were assessed. The podocyte injury was evaluated, and the NLRP3 in podocytes of mice was detected. Notch1 pathway was overactivated in glomeruli of LN patients. NICD1 was colocalized with podocytes of LN patients and MRL/lpr mice. The inflammasome-related genes were significantly increased in podocytes with PAN treatment. NICD1 and NLRP3 were significantly decreased, while WT1 was significantly increased in injured podocytes treated with DAPT in vitro. In vivo, lupus-like symptoms were alleviated in DAPT treatment group. Notch1 pathway was inhibited in kidneys of mice treated with DAPT. The renal inflammation was reduced and the podocyte injury was mitigated in DAPT treatment group. The NLRP3 was decreased in podocytes of mice treated with DAPT. Notch1 pathway was overactivated in podocytes of LN patients and MRL/lpr mice. Blockade of Notch1 pathway reduced renal inflammation and alleviated podocyte injury via inhibition of NLRP3 inflammasome activation in LN.

Immunoglobulin A glomerulonephropathy: A review

In this editorial, we comment on the article by Meng et al published in the World Journal of Clinical Cases. We comprehensively review immunoglobulin A nephropathy (IgAN), including epidemiology, clinical presentation, diagnosis, and management. IgAN, also known as Berger's disease, is the most frequent type of primary glomerulonephritis (GN) globally. It is mostly found among the Asian population. The presentation can be variable, from microscopic hematuria to a rapidly progressive GN. Around 50% of patients present with single or recurring episodes of gross hematuria. An upper respiratory infection and tonsillitis often precede these episodes. Around 30% of patients present microscopic hematuria with or without proteinuria, usually detected on routine examination. The diagnosis relies on having a renal biopsy for pathology and immunofluorescence microscopy. We focus on risk stratification and management of IgAN. We provide a review of all the landmark studies to date. According to the 2021 KDIGO (kidney disease: Improving Global Outcomes) guidelines, patients with non-variant form IgAN are first treated conservatively for three to six months. This approach consists of adequate blood pressure control, reduction of proteinuria with renin-angiotensin system blockade, treatment of dyslipidemia, and lifestyle modifications (weight loss, exercise, smoking cessation, and dietary sodium restrictions). Following three to six months of conservative therapy, patients are further classified as high or low risk for disease progression. High-risk patients have proteinuria ≥ 1 g/d or < 1 g/d with significant microscopic hematuria and active inflammation on kidney biopsy. Some experts consider proteinuria ≥ 2 g/d to be very high risk. Patients with high and very high-risk profiles are treated with immunosuppressive therapy. A proteinuria level of < 1 g/d and stable/improved renal function indicates a good treatment response for patients on immunosuppressive therapy.

Kidney outcomes associated with haematuria and proteinuria trajectories among patients with IgA nephropathy in real-world clinical practice: The Japan Chronic Kidney Disease Database

AIM

Among patients with Immunoglobulin A (IgA) nephropathy, we aimed to identify trajectory patterns stratified by the magnitude of haematuria and proteinuria using repeated urine dipstick tests, and assess whether the trajectories were associated with kidney events.

METHODS

Using a nationwide multicentre chronic kidney disease (CKD) registry, we analysed data from 889 patients with IgA nephropathy (mean age 49.3 years). The primary outcome was a sustained reduction in eGFR of 50% or more from the index date and thereafter. During follow-up (median 49.0 months), we identified four trajectories (low-stable, moderate-decreasing, moderate-stable, and high-stable) in both urine dipstick haematuria and proteinuria measurements, respectively.

RESULTS

In haematuria trajectory analyses, compared to the low-stable group, the adjusted hazard ratios (HRs) (95% confidence interval [CI]) for kidney events were 2.59 (95% CI, 1.48-4.51) for the high-stable, 2.31 (95% CI, 1.19-4.50) for the moderate-stable, and 1.43 (95% CI, (0.72-2.82) for the moderate-decreasing groups, respectively. When each proteinuria trajectory group was subcategorized according to haematuria trajectories, the proteinuria group with high-stable and with modest-stable haematuria trajectories had approximately 2-times higher risk for eGFR reduction ≥50% compared to that with low-stable haematuria trajectory.

CONCLUSION

Assessments of both haematuria and proteinuria trajectories using urine dipstick could identify high-risk IgA nephropathy patients.

The association of normal-range serum phosphorus with immunoglobulin A nephropathy progression: a retrospective cohort study

PURPOSE

The relationship between serum phosphorus and immunoglobulin A (IgA) nephropathy progression remains uncertain, especially normal-range serum phosphorus. Therefore, we herein examined the relationship between the normal-range serum phosphorus and the progression of IgA nephropathy.

METHODS

One hundred sixty-two patients with primary IgA nephropathy were divided into three groups according to tertiles of baseline serum phosphorus (first tertile: 0.73-1.04 mmol/L; second tertile: 1.04-1.21 mmol/L; third tertile: 1.21-1.60 mmol/L). Estimated glomerular filtration rate (eGFR) was calculated using the chronic kidney disease epidemiology collaboration. The composite outcome was defined as a decrease of at least 50% in eGFR from baseline or end-stage kidney disease (ESKD). The association of serum phosphorus with IgA nephropathy progression was estimated using Cox proportional hazards models, adjusting for potential confounders.

RESULTS

During a median 16 month follow-up period, 15 patients reached a composite outcome. In the crude Cox proportional hazard model, baseline serum phosphorus as a continuous variable was associated with increased risk for adverse renal outcomes [hazard ratio (HR) = 63.510, 95% confidence interval (CI) = 3.953-1020.284, P = 0.003], and the high tertile of serum phosphorus group had an increased risk of the composite outcome by using the low tertile group as the reference (HR = 11.895, 95% CI = 1.522-92.993, P = 0.018). After adjustment for traditional risk factors, the high tertile of serum phosphorus group was significantly related to IgA nephropathy progression compared with the low tertile group (HR = 9.424, 95% CI = 1.019-87.165, P = 0.048).

CONCLUSIONS

Relatively higher serum phosphorus levels within the normal range were significantly associated with the progression of IgA nephropathy.

Changes in spectrum of biopsy-proven kidney diseases within decade: an analysis based on 10 199 cases from South China

PURPOSE

To assess the regional epidemiological trends of kidney diseases over time in the South China using renal biopsy-proven cases.

METHODS

This retrospective observational cohort study was conducted at the Institute of Nephrology, Second Xiangya Hospital of Central South University, and encompasses all patients diagnosed with kidney disease via biopsy from 2012 to 2021.

RESULTS

The study sample consisted of 10 199 native kidneys, with a male-to-female ratio of 0.91:1 and an average age of 38.74 (±14.53) years. Primary glomerular nephropathy, systemic glomerular nephropathy (SGN), tubulointerstitial disease, and hereditary renal diseases accounted for 66.92 (6825)%, 24.49 (2498)%, 8.06 (822)%, and 0.53 (54)%, respectively. The leading pathologies of primary glomerular nephropathy remained the IgA nephropathy. The frequencies of IgA nephropathy and membranous nephropathy increased significantly, whereas the frequencies of minimal change disease and focal segmental glomerulosclerosis decreased (P < .001) between 2017 and 2021 than in the years 2012 and 2016. An earlier onset of membranous nephropathy was observed in the age group of 45-59 years compared to previous studies. The leading pathologies of SGN were found to be lupus nephritis (758 cases, 30.45%) and hypertension nephropathy (527 cases, 21.17%). The frequencies of hypertension nephropathy and diabetic nephropathy increased between 2017 and 2021 compared to 2012 and 2016 (P < .001), gradually becoming the leading pathological types of SGN. In elderly patients diagnosed with nephrotic syndrome, the frequencies of amyloidosis significantly increased (P < .01).

CONCLUSION

Our study may provide insights for kidney disease prevention and public health strategies. What is already known on this topic The pathological spectrum of kidney diseases has undergone significant transformations in the past decade, driven by the escalating incidence of chronic diseases. Although there are studies exploring the renal biopsy findings from various regions in China which present both similarities and differences in epidemiology, few large-scale reports from the South China in recent decades were published. What this study adds Our findings reveal the following key observations: (i) increased proportion of middle-aged patients leading to the increasing average age at the time of biopsy；(ii) the frequencies of IgA nephropathy and membranous nephropathy (MN) increased significantly, whereas the frequencies of minimal change disease and focal segmental glomerulosclerosis decreased (P < .001) between 2017 and 2021 than in the years 2012 and 2016; (iii) earlier onset of MN in the age group of 45-59 years old was found in our study; and (iv) a higher frequency of hypertension nephropathy and DN presented over time, and frequency of amyloidosis increased in elderly patients diagnosed with NS. How this study might affect research, practice, or policy This single-center yet a large-scale study of the kidney disease spectrum in South China may provide a reference point for the diagnosis, treatment, and prevention of chronic kidney disease.

Mild mesangial proliferative IgA nephropathy with and without minimal change disease

Mild mesangial proliferative IgA nephropathy with minimal change disease (MCD-IgAN) and mild mesangial proliferative IgA nephropathy without minimal change disease (Non-MCD-IgAN) have similar characteristics on light microscopy. Nevertheless, their discrepancies in clinicopathological features and prognosis remain unknown. A total of 589 patients with biopsy-proven mild mesangial proliferative IgA nephropathy (M-IgAN) combined with light microscopy and immunofluorescence were enrolled. Firstly, the diagnoses of the patients by electron microscopy were recorded and used as the gold standard. We calculated the sensitivity and specificity using nephrotic syndrome (NS) as the diagnostic criteria to identify MCD-IgAN. Then, excluding patients with a 24-h urinary total protein less than 0.5 g/day, incomplete clinical data, or less than the six-month follow-up, we included 184 cases of non-MCD-IgAN and 98 cases of MCD-IgAN. The patients' clinicopathological and outcome data were collected and compared. Among the 589 patients, according to electron microscopy, 381 were diagnosed with non-MCD-IgAN, 167 with MCD-IgAN, and 41 with M-IgAN complicated by other glomerular diseases. Using NS as the diagnostic criteria to distinguish non-MCD-IgAN and MCD-IgAN, the sensitivity and specificity were 83.8% and 99.5%, respectively. The patients in the MCD-IgAN group tended to be younger, hypotensive, with lower urinary erythrocytes, and more likely to achieve complete remission, and fewer patients progressed to the endpoint than those in the non-MCD-IgAN group (all P < 0 .05). NS appears to be an objective indicator for differentiating MCD-IgAN from non-MCD-IgAN. Non-MCD-IgAN varies greatly from MCD-IgAN in clinicopathology and treatment response, with a poorer prognosis.

Is serum hemoglobin level an independent prognostic factor for IgA nephropathy?: a systematic review and meta-analysis of observational cohort studies

BACKGROUND

Decreased serum hemoglobin (Hb) level is associated with Immunoglobulin A nephropathy (IgAN) progression. However, whether serum Hb level is an independent prognostic factor of IgAN remains controversial. Herein, we aimed to investigate the prognostic value of serum Hb level in IgAN.

METHODS

The Cochrane Library, Embase, PubMed and Open Grey databases were systematically searched and reviewed. Kidney disease progression of IgAN was defined as a doubling of serum creatinine (SCr), a 30% reduction in estimated glomerular filtration rate (eGFR), end-stage renal disease (ESRD), or death. We evaluated the hazard ratio (HR) between serum Hb level and the incidence of kidney disease progression in IgAN before and after adjusting for relevant covariates.

RESULTS

We included nine studies with 10006 patients in the meta-analysis. As a continuous variable, we found that serum Hb was an independent prognostic factor of IgAN [unadjusted HR = 0.89, 95% confidence interval (CI) = 0.84-0.95, I² = 98%; adjusted HR = 0.85, 95% CI = 0.79-0.91, I² = 0%]. The sensitivity analysis confirmed the stability of these results. Consistently, as a dichotomous variable defined as the below/above cutoff for anemia, we observed a positive correlation between serum Hb and kidney disease progression in IgAN (unadjusted HR = 2.12, 95% CI = 1.44-3.12, I² = 79%; adjusted HR = 1.65, 95% CI = 1.20-2.27, I² = 0%).

CONCLUSION

Serum Hb level was independently correlated with the incidence of kidney disease progression in IgAN.

Candidate Genes for IgA Nephropathy in Pediatric Patients: Exome-Wide Association Study

IgA nephropathy (IgAN) is an autoimmune disorder which is believed to be non-monogenic. We performed an exome-wide association study of 70 children with IgAN and 637 healthy donors. The HLA allele frequencies were compared between the patients and healthy donors from the bone marrow registry of the Pirogov University. We tested 78,020 gene markers for association and performed functional enrichment analysis and transcription factor binding preference detection. We identified 333 genetic variants, employing three inheritance models. The most significant association with the disorder was observed for rs143409664 (PRAG1) in the case of the additive and dominant models (PBONF = 1.808 × 10-15 and PBONF = 1.654 × 10-15, respectively), and for rs13028230 (UBR3) in the case of the recessive model (PBONF = 1.545 × 10-9). Enrichment analysis indicated the strongly overrepresented "immune system" and "kidney development" terms. The HLA-DQA1*01:01:01G allele (p = 0.0076; OR, 2.021 [95% CI, 1.322-3.048]) was significantly the most frequent among IgAN patients. Here, we characterized, for the first time, the genetic background of Russian IgAN patients, identifying the risk alleles typical of the population. The most important signals were detected in previously undescribed loci.

Urinary peptidome analysis in CKD and IgA nephropathy

Background

Chronic kidney disease (CKD) has emerged as a significant challenge to human health and economic stability in aging societies worldwide. Current clinical practice strategies remain insufficient for the early identification of kidney dysfunction, and the differential diagnosis of immunoglobulin A nephropathy (IgAN) predominantly relies on invasive kidney biopsy procedures.

Methods

First, we assessed a case-control cohort to obtain urine samples from healthy controls and biopsy-confirmed CKD patients. Matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) was applied to detect urinary peptide and then these urinary peptide profiles were used to construct diagnostic models to distinguish CKD patients from controls and identify IgAN patients from other nephropathy patients. Furthermore, we assessed the robustness of the diagnostic models and their reproducibility by applying different algorithms.

Results

A rapid and accurate working platform for detecting CKD and its IgAN subtype based on urinary peptide pattern detected by MALDI-TOF MS was established. Naturally occurring urinary peptide profiles were used to construct a diagnostic model to distinguish CKD patients from controls and identify IgAN patients from other nephropathy patients. The performance of several algorithms was assessed and demonstrated that the robustness of the diagnostic models as well as their reproducibility were satisfactory.

Conclusions

The present findings suggest that the CKD-related and IgAN-specific urinary peptides discovered facilitate precise identification of CKD and its IgAN subtype, offering a dependable framework for screening conditions linked to renal dysfunction. This will aid in comprehending the pathogenesis of nephropathy and identifying potential protein targets for the clinical management of nephropathy.

Clinical significance of IgM and C3 deposition in children with primary immunoglobulin A nephropathy

BACKGROUND

Mesangial IgM and C3 deposition is commonly observed in patients with primary immunoglobulin A nephropathy (IgAN), but its characteristics and prognosis have rarely been reported. The aim of this study was to investigate the relationship between combined mesangial IgM and C3 deposition and disease progression in children with IgAN.

METHODS

One hundred sixteen children diagnosed with IgAN between 2016 and 2020 were selected. Renal biopsies were scored by Oxford classification including the presence of mesangial hypercellularity, endocapillary hypercellularity, segmental glomerulosclerosis, tubular atrophy/interstitial fibrosis and crescents. The primary renal outcome was an event of either ≥ 50% reduction of eGFR from the baseline value or the onset of end-stage renal disease within the follow-up period. Cox regression analysis was performed to examine the effect of the combined mesangial IgM and C3 deposition on renal outcomes.

RESULTS

Forty-seven (40.52%) patients presented combined mesangial IgM and C3 deposition. Compared with children without combined IgM and C3 deposition, children with combined IgM and C3 deposition presented higher mesangial hypercellularity, endocapillary hypercellularity and cresentic lesions in kidney biopsies, and higher prevalence of renal dysfunction (19.15% versus 2.90%; P = 0.007). Renal outcome was also significantly worse as revealed by Kaplan-Meier curves (P = 0.0034). Multivariable Cox analysis identified tubular atrophy/interstitial fibrosis lesions [hazard ratio (HR) 14.843, 95% CI, 3.497-62.997, P < 0.001] and intensity of IgM deposition (HR 2.838, 95% CI, 1.321-6.094, P = 0.007) as independent risk factors for poor renal function.

CONCLUSIONS

Combined mesangial IgM and C3 deposition was associated with unfavorable histopathological features. Mesangial IgM deposition was an independent risk factor for poor renal outcomes in children with primary IgAN.

Containing anti-PLA2R IgG antibody induces podocyte injury in idiopathic membranous nephropathy

Background: Idiopathic membranous nephropathy is widely recognized as an autoimmune kidney disease that is accompanied by the discovery of several autoantibodies, and the antibody subclass in the circulation of patients with iMN is mainly IgG. However, the direct pathogenic effect of the containing anti-PLA2R IgG antibody on podocytes is not clear.Method: A protein G affinity chromatography column was used to purify serum IgG antibodies. Containing anti-PLA2R IgG antibodies from iMN patients and IgG from healthy controls were also obtained. Based on the established in vitro podocyte culture system, purified IgG antibodies from the two groups were used to stimulate podocytes, and the expression of essential podocyte proteins (podocin), the levels of inflammatory cytokines in the cell supernatant, cytoskeletal disorders, and podocyte apoptosis were analyzed.Results: Compared with that in the normal IgG group, the expression of podocin and podocin mRNA was reduced (p = 0.016 and p = 0.005, respectively), the fluorescence intensity of podocin on the surface of podocytes was reduced, the cytoskeleton of podocytes was disordered and reorganized, and the ratio of podocyte apoptosis was increased in the iMN group (p = 0.008).Conclusion: The containing anti-PLA2R IgG antibody might have a direct damaging effect on podocytes in idiopathic membranous nephropathy.

Development of a novel combined nomogram model integrating deep learning radiomics to diagnose IgA nephropathy clinically

This study aimed to develop and validate a combined nomogram model based on superb microvascular imaging (SMI)-based deep learning (DL), radiomics characteristics, and clinical factors for noninvasive differentiation between immunoglobulin A nephropathy (IgAN) and non-IgAN.We prospectively enrolled patients with chronic kidney disease who underwent renal biopsy from May 2022 to December 2022 and performed an ultrasound and SMI the day before renal biopsy. The selected patients were randomly divided into training and testing cohorts in a 7:3 ratio. We extracted DL and radiometric features from the two-dimensional ultrasound and SMI images. A combined nomograph model was developed by combining the predictive probability of DL with clinical factors using multivariate logistic regression analysis. The proposed model's utility was evaluated using receiver operating characteristics, calibration, and decision curve analysis. In this study, 120 patients with primary glomerular disease were included, including 84 in the training and 36 in the test cohorts. In the testing cohort, the ROC of the radiomics model was 0.816 (95% CI:0.663-0.968), and the ROC of the DL model was 0.844 (95% CI:0.717-0.971). The nomogram model combined with independent clinical risk factors (IgA and hematuria) showed strong discrimination, with an ROC of 0.884 (95% CI:0.773-0.996) in the testing cohort. Decision curve analysis verified the clinical practicability of the combined nomogram. The combined nomogram model based on SMI can accurately and noninvasively distinguish IgAN from non-IgAN and help physicians make clearer patient treatment plans.

RhoA vesicle trafficking-mediated transglutaminase 2 membrane translocation promotes IgA1 mesangial deposition in IgA nephropathy

Transglutaminase 2 (TGase2) has been shown to contribute to the mesangial IgA1 deposition in a humanized mouse model of IgA nephropathy (IgAN), but the mechanism is not fully understood. In this study, we found that inhibition of TGase2 activity could dramatically decrease the amount of polymeric IgA1 (pIgA1) isolated from patients with IgAN that interacts with human mesangial cells (HMC). TGase2 was expressed both in the cytosol and on the membrane of HMC. Upon treatment with pIgA1, there were more TGase2 recruited to the membrane. Using a cell model of mesangial deposition of pIgA1, we identified 253 potential TGase2-associated proteins in the cytosolic fraction and observed a higher concentration of cellular vesicles and increased expression of Ras homolog family member A (RhoA) in HMC after pIgA1 stimulation. Both the amount of pIgA1 deposited on HMC and membrane TGase2 level were decreased by inhibition of the vesicle trafficking pathway. Mechanistically, TGase2 was found to be coprecipitated with RhoA in the cellular vesicles. Membrane TGase2 expression was greatly increased by overexpression of RhoA, while it was reduced by knockdown of RhoA. Our in vitro approach demonstrated that TGase2 was transported from the cytosol to the membrane through a RhoA-mediated vesicle-trafficking pathway that can facilitate pIgA1 interaction with mesangium in IgAN.

Spectrum and Distribution of Biopsy-proven Kidney Diseases: A 12-year Survey of a Single Center in Iran

Data about the prevalence of biopsy-proven kidney diseases in Iran are rare, and none of the previous studies used electron microscopy for diagnosis. This study aimed to analyze the prevalence of biopsy-proven kidney diseases in Iran's primary referral center. To the best of our knowledge, this is the most extensive study carried out in Iran. Reports of kidney biopsy samples from patients referred to our center in 2007-2018 were reviewed for demographic data, clinical presentation, and final diagnosis. Statistical analyses were performed. Among the 3455 samples received, 2975 were analyzed. Nephrotic syndrome (39%) was the most common cause of biopsy, followed by subnephrotic proteinuria (18%), hematuria in association with proteinuria (15%), renal failure (9%), isolated hematuria (6%), and lupus nephritis (LN) (4%). The most common diagnoses were membranous glomerulonephritis (17.9%), focal segmental glomerulosclerosis (FSGS) (15.9%), LN (13.7%), minimal histopathological findings (unsampled FSGS vs. minimal change disease, 12.1%), Immunoglobin A nephropathy (IgAN) (6.5%) and Alport syndrome (6.1%). NS and proteinuria were the most common indications for a kidney biopsy. IgAN and LN were the most common causes of primary and secondary glomerulonephritis, presenting with hematuria and proteinuria, respectively. Although membranous glomerulonephritis was the most common disease, it has been replaced by FSGS in recent years.

Clinicopathological spectrum of biopsy-proven renal diseases of patients at a single center in Sri Lanka: a cross sectional retrospective review

BACKGROUND

The clinical presentation of renal diseases can vary widely. The lack of a comprehensive national registry for Sri Lanka makes it difficult to provide a detailed record of the various clinical presentations and histopathology of renal disorders in the nation. Therefore, this study aims to provide a record of the spectrum of renal diseases in Sri Lanka.

METHODS

Renal biopsies performed at the nephrology unit in Colombo South Teaching Hospital (CSTH), Sri Lanka from March 2018 to October 2019 was retrospectively studied. Indications for renal biopsy were nephrotic range proteinuria, sub nephrotic range proteinuria, acute kidney injury without obvious etiology, chronic renal disease without obvious etiology and haematuria.

RESULTS

A total of 140 native kidney biopsies were analyzed in which majority were females (55.7%). The mean age of the population was 46 ± 15.3 years. The most common indications for renal biopsy were nephrotic range proteinuria (54.3%), followed by sub-nephrotic range proteinuria (14.3%), nephrotic range proteinuria with haematuria (14.3%), sub-nephrotic range proteinuria with haematuria (9.3%), AKI without known cause (4.3%), and CKD without known cause (3.6%). The leading histopathological diagnoses were FSGS (22.1%), lupus nephritis (20%), PSGN (17.1%), DN (12.1%), HTN (9.3%), MCD (6.4%), IgA nephropathy (5.7%), IN (4.3%), vasculitis (2.1%), and MGN (0.7%).

CONCLUSIONS

The most common indication for renal biopsy was nephrotic range proteinuria in our population. FSGS was the most prevalent histopathological diagnosis and the least frequent diagnosis reported was MGN. The spectrum of renal diseases could differ according to the study location and it changes over time. Therefore, a renal biopsy registry is needed for documenting the changing disease pattern in Sri Lanka.

Systematic Microbiome Dysbiosis Is Associated with IgA Nephropathy

IgA nephropathy (IgAN) is reportedly associated with microbial dysbiosis. However, the microbiome dysregulation of IgAN patients across multiple niches remains unclear. To gain a systematic understanding of microbial dysbiosis, we conducted large-scale 16S rRNA gene sequencing in IgAN patients and healthy volunteers across 1,732 oral, pharynx, gut, and urine samples. We observed a niche-specific increase of several opportunistic pathogens, including Bergeyella and Capnocytophaga in the oral and pharynx, whereas some beneficial commensals decreased in IgAN patients. Similar alterations were also observed in the early versus advanced stage of chronic kidney disease (CKD) progression. Moreover, Bergeyella, Capnocytophaga, and Comamonas in the oral and pharynx were positively associated with creatinine and urea, indicating renal lesions. Random forest classifiers were developed by using the microbial abundance to predict IgAN, achieving an optimal accuracy of 0.879 in the discovery phase and 0.780 in the validation phase. IMPORTANCE This study provides microbial profiles of IgAN across multiple niches and underlines the potential of these biomarkers as promising, noninvasive tools with which to differentiate IgAN patients for clinical applications.

An update on corticosteroid treatment for IgA nephropathy

PURPOSE OF REVIEW

The use of corticosteroids to treat IgA nephropathy (IgAN) has been limited by many controversies related to uncertain benefit and safety concerns. Recent trials have tried to address these limitations.

RECENT FINDINGS

After being paused because of an excess of adverse events in the full-dose steroid arm, the TESTING trial compared a reduced dose of methylprednisolone to placebo in patients with IgAN after optimization of supportive therapy. Steroid treatment was associated with a significant reduction in the risk of a 40% decline in estimated glomerular filtration rate (eGFR), kidney failure and kidney death as well as a sustained decrease in proteinuria compared with placebo. Serious adverse events were more frequent with the full dose regimen but less common in the reduced dose regimen. A phase III trial evaluating a new formulation of targeted-release budesonide showed a significant reduction in short-term proteinuria and has resulted in accelerated FDA approval for use in the United States. In a subgroup analysis of DAPA-CKD trial, sodium-glucose transport protein 2 inhibitors reduced the risk of kidney function decline in patients who have completed or are not eligible for immunosuppression.

SUMMARY

Both reduced-dose corticosteroids and targeted-release budesonide are new therapeutic options that can be used in patients with high-risk disease. More novel-targeted therapies with a better safety profile are currently under investigations.

Clinicopathological Characteristics and Outcomes of Immunoglobulin A Nephropathy with Different Types of Dyslipidemia: A Retrospective Single-Center Study

INTRODUCTION

Immunoglobulin A nephropathy (IgAN) is one of the most common glomerulonephritic diseases in the world. Several lines of evidence have suggested that dyslipidemia is related to the disease progression and prognosis of IgAN. However, the study is scarce on the clinicopathological characteristics and outcomes of IgAN with dyslipidemia.

METHODS

This study retrospectively analyzed 234 patients with biopsy-proven idiopathic IgAN at the Department of Nephrology, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, between January 2015 and June 2021. The participants were divided into dyslipidemia (n = 119) and non-dyslipidemia (n = 115), and the dyslipidemia group was also divided into the following 4 groups: hypertriglyceridemia group, hypercholesterolemia group, mixed hyperlipidemia group, and low high-density lipoprotein cholesterol group. The estimated glomerular filtration rate (eGFR) was estimated by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation.

RESULTS

The prevalence of dyslipidemia in IgAN patients in our center was 50.9% (119/234). The patients with dyslipidemia presented with higher systolic blood pressure (BP), diastolic BP, serum creatinine, uric acid, hemoglobin, proteinuria, and eGFR (p < 0.05). Proportions of males, hypertension, and chronic kidney disease stage 2∼5 were also higher in the dyslipidemia group (p < 0.05). Similarly, the pathological characteristics performed were worse in the dyslipidemia group. Most dyslipidemia patients had a higher percentage of mesangial hypercellularity (M1) and tubular atrophy/interstitial fibrosis (T1∼2) in the Oxford Classification's scoring system (p < 0.05). Multivariate logistic regression analysis revealed that male gender (odds ratio [OR] = 2.397, 95% confidence interval [CI]: 1.051-5.469, p = 0.038) and proteinuria (OR = 1.000, 95% CI: 1.000-1.001, p = 0.035) were possible risk factors for dyslipidemia. A total of 13 patients (13.8%) in the dyslipidemia group had an endpoint event, of which 6 patients (6.4%) had a ≥50% decrease in eGFR from baseline and 7 patients (7.4%) reached the end-stage renal disease stage. Kaplan-Meier survival curve analysis showed that patients in the dyslipidemia group had a worse outcome than those in the non-dyslipidemia group (log-rank test, p = 0.048).

CONCLUSIONS

IgAN patients with dyslipidemia presented more severe clinicopathological characteristics. Male gender and proteinuria are significantly associated with the occurrence of dyslipidemia in IgAN patients. Patients in the dyslipidemia group had a worse prognosis than those in the non-dyslipidemia group, which may be essential for the disease management of IgAN and help identify the high-risk patients.

Demographic, clinical and laboratory characteristics of adult-onset minimal change disease in Turkey: Turkish Society of Nephrology-Glomerular Diseases (TSN-GOLD) Working Group

PURPOSE

In our study, diagnostic and demographic characteristics of patients diagnosed with minimal change disease (MCD) by biopsy, clinical and laboratory findings in our country were investigated.

METHODS

Data were obtained from the Turkish Society of Nephrology Glomerular Diseases (TSN-GOLD) Working Group database. Demographic characteristics, indications for biopsy, diagnosis of the glomerular diseases, comorbidities, laboratory and biopsy findings of all patients were recorded. The data presented are cross-sectional and includes application data for the biopsy period.

RESULTS

Of 3875 patients, 233 patients with MCD (median age 35.0 years) were included in the study, which constitutes 6.0% of the total glomerulonephritis database. Renal biopsy was performed in 196 (84.1%) patients due to nephrotic syndrome. Median serum creatinine was 0.7 (0.6-1.0) mg/dl, mean eGFR was 104 ± 33 ml/min/1.73 m² and median proteinuria 6000 mg/day. The number of patients under the age of 40 years was 139 (59.7%) (Group A), and the number of patients aged 40 years and over was 94 (40.3%) (Group B). Compared to Group A, global sclerotic glomeruli (24 vs. 43, p < 0.001) interstitial inflammation (15 vs. 34, p < 0.001), interstitial fibrosis (20 vs. 31, p = 0.001, vascular changes (10 vs. 25, p < 0.001) and tubular atrophy (18 vs. 30, p < 0.001) were found to be significantly higher in Group B. There was no difference in immunofluorescent staining properties between the two groups.

CONCLUSION

Our data are generally compatible with the literature. Chronic histopathological changes were more common in patients aged 40 years and older than younger patients. Studies investigating the effects of these different features on renal survival are needed.

Discovery of Fibrinogen γ-chain as a potential urinary biomarker for renal interstitial fibrosis in IgA nephropathy

BACKGROUND

IgA nephropathy (IgAN) is a major cause of chronic kidney disease (CKD). Renal interstitial fibrosis is a hallmark of CKD progression. Non-invasive biomarkers are needed to dynamically evaluate renal fibrosis. Data independent acquisition (DIA)-based liquid chromatography-mass spectrometry (DIA-MS) was used to identify candidate urinary biomarkers in IgAN patients with different renal interstitial fibrosis degrees.

METHODS

Eighteen biopsy-proven IgAN patients and six healthy controls were recruited in a discovery cohort. Interstitial fibrosis changes were evaluated according to Oxford MEST-C scores. Urinary samples were analyzed with DIA-MS to identify hub proteins. Hub proteins were then confirmed by enzyme-linked immunosorbent assay (ELISA) in a validation cohort and the associated gene mRNA expression was analyzed using public gene expression omnibus (GEO) datasets.

RESULTS

Complement and coagulation cascades pathway was the main KEGG pathway related to the over-expressed proteins. Fibrinogen γ-Chain (FGG) was selected as the potential urinary marker for further validation. Urinary FGG to creatinine ratio (uFGG/Cr) levels were higher in both disease controls and IgAN group than in healthy controls, but were not significantly different between IgAN and disease groups. uFGG/Cr was confirmed to be increased with the extent of renal fibrosis and presented moderate correlations with T score (r = 0.614, p < 0.01) and eGFR (r = -0.682, p < 0.01), and a mild correlation with UTP (r = 0.497, p < 0.01) in IgAN group. In disease control group, uFGG/Cr was higher in patients with T1 + 2 compared to those with T0. uFGG/Cr had a good discriminatory power to distinguish different fibrosis stages in IgAN: interstitial fibrosis ≤ 5% (minimal fibrosis) vs. interstitial fibrosis (mild fibrosis) > 5%, AUC 0.743; T0 vs. T1 + 2, AUC 0.839; T0 + 1 vs. T2, AUC 0.854. In disease control group, uFGG/Cr showed better performance of AUC than UTP between minimal and mild fibrosis (p = 0.038 for Delong's test). Moreover, GSE104954 dataset showed that FGG mRNA expression was up-regulated (fold change 1.20, p = 0.009) in tubulointerstitium of IgAN patients when compared to healthy living kidney donors.

CONCLUSION

Urinary FGG is associated with renal interstitial fibrosis and could be used as a noninvasive biomarker for renal fibrosis in IgAN.

Divergent manifestations and outcomes of diffuse crescentic immunoglobulin A nephropathy and pauci-immune crescentic glomerulonephritis on long-term

BACKGROUND

Diffuse crescentic IgAN (CIgAN) is an uncommon phenotype of IgAN, which presents as rapidly progressive renal failure, similar to patients with pauci-immune crescentic glomerulonephritis(PCGN). There are limited data on outcomes comparisons between the two.

METHODS

In this single-center, retrospective cohort study, we compared the clinical features, pathological presentation, and renal outcomes of 52 patients with CIgAN and 42 patients with renal-limited PCGN from January 2007 to December 2019.

RESULTS

The CIgAN patients were younger (30.5 ± 13.8 years) than PCGN patients (46.1 ± 11.8 years) (P = 0.001). The CIgAN patients had a higher prevalence of hypertension (86.5% Vs. 41.3%, P = 0.001); and degree of proteinuria (4.2 ± 2.7 g/24 h Vs. 2.3 ± 1.16 g/24 h; P = 0.001) than PCGN patients. The chronicity in terms of global glomerulosclerosis, interstitial fibrosis, and tubular atrophy was higher in the CIgAN group than in the PCGN group. The remission rate with immunosuppression was significantly higher in the PCGN group than in the CIgAN group (P = 0.016). The end-stage renal disease (ESRD) or death within 1 year of diagnosis was significantly more in the CIgAN group (62.3% Vs. 39.1%) than PCGNgroup. For patients who were dialysis-dependent at presentation, the primary outcome of ESRD or death within one year was seen in 90.9% of patients of CIgAN and 44.1% in the PCGN group (P = 0.001). The long-term death non-censored renal survival is poor in the CIgAN group than in PCGN patients. However, patient survival is poor in PCGN patients.

CONCLUSION

CIgAN is a different form of RPGN compared to PCGN and carries a poor prognosis despite similar immunosuppressive therapy in the long term.

New-onset IgA nephropathy following COVID-19 vaccination

Coronavirus disease 2019 (COVID-19) pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has caused significant economic and health damage worldwide. Rapid vaccination is one of the key strategies to curb severe illness and death due to SARS-CoV-2 infection. Hundreds of millions of people worldwide have received various COVID-19 vaccines, including mRNA vaccines, inactivated vaccines and adenovirus-vectored vaccines, but the side effects and efficacy of most vaccines have not been extensively studied. Recently, there have been increasing reports of immunoglobulin A nephropathy (IgAN) after COVID-19 vaccination, however, whether their relationship is causal or coincidental remains to be verified. Here, we summarize the latest clinical evidence of IgAN diagnosed by renal biopsy associated with the COVID-19 vaccine published by 10 July 2022 with the largest sample size, and propose a hypothesis for the pathogenesis between them. At the same time, the new opportunity presented by COVID-19 vaccine allows us to explore the mechanism of IgAN recurrence for the first time. Indeed, we recognize that large-scale COVID-19 vaccination has enormous benefits in preventing COVID-19 morbidity and mortality. The purpose of this review is to help guide the clinical assessment and management of IgA nephropathy post-COVID-19 vaccination and to enrich the 'multi-hit' theory of IgA nephropathy.

Podocytes are likely the therapeutic target of IgA nephropathy with isolated hematuria: Evidence from repeat renal biopsy

Background: The present study aimed to prove the progression of immunoglobulin A nephropathy (IgAN) patients with isolated hematuria based on repeat renal biopsy data for the first time. Methods: 29 IgAN patients with isolated hematuria who received repeat renal biopsies were analyzed retrospectively, while 29 non-isolated hematuria IgAN patients with similar age and background were randomly selected as the control group. Clinical parameters were collected at the time of biopsy. The treatment strategies (conservative treatment with RASS blocker or immunosuppressive treatment) were choosen according to the pathological results at the first renal biopsy. The activity and chronicity indexes of renal lesions were evaluated. Markers of cell inflammation and proliferation were tseted by immunochemistry. The ultrastructure of podocytes was observed by transmission electron microscopy (TEM). Podocyte and oxidative stress marker (NPHS2 and 4-HNE) were detected by immunofluorescence. Results: The IgAN patients with isolated hematuria had better clinical indicators than those with no-isolated hematuria, such as better renal function, higher albumin and lower uric acid. The interval between two biopsies in IgAN patients with isolated hematuria was 630 (interquartile range, 409.5-1,171) days. The hematuria of the patients decreased significantly from 30 (IQR, 4.00-35.00) RBC/ul in the first biopsy to 11 (IQR, 2.50-30.00) RBC/ul in the repeated biopsy (p < 0.05). The level of triglyceride decreased significantly (p < 0.05). The other clinical indicators were not statistically significant (p > 0.05). Deposits of IgA and C3 in the glomerulus were persistent. The activity index decreased, especially cellular crescent formation, while the chronicity index increased. The ultrastructure of podocytes was improved after treatment. The oxidative stress products of podocytes reduced after treatment. Conclusion: Although the clinical indicators of the IgAN patients with isolated hematuria were in the normal range, various acute and chronic pathological changes have occurred, and irreversible chronic changes have been progressing. Cell inflammation and proliferation persisted. Oxidative stress of podocytes was likely to be the therapeutic target. This study provided a strong basis for the progress of IgAN with isolated hematuria through pathological changes before and after treatment. This study will help clinicians recognize the harm of hematuria, change the traditional treatment concept, and help such patients get early treatment.

Efficacy and indications of tonsillectomy in patients with IgA nephropathy: a retrospective study

Background

The efficacy and indications of tonsillectomy in IgA nephropathy (IgAN) remain uncertain.

Methods

We performed a retrospective cohort study of 452 patients with primary IgAN, including 226 patients who received tonsillectomy and 226 controls selected by propensity score matching who had never undergone tonsillectomy. Study outcomes were clinical remission defined as negative hematuria and proteinuria on three consecutive visits over a 6-month period, the endpoint defined as end-stage renal disease or an irreversible 100% increase in serum creatinine from the baseline value. In addition, we further analyzed the critical level of proteinuria in the efficacy of tonsillectomy and the correlation between MEST-C score and tonsillectomy.

Results

Up to December 2019, the follow-up period lasted 46 ± 23 months (12-106 months). Kaplan-Meier and multivariate Cox regression analysis revealed that tonsillectomy was beneficial for clinical remission and renal survival. Whether proteinuria was ≤ 1 g/24h or >1 g/24h, the clinical remission and renal survival rates were greater in patients treated with tonsillectomy than without. When the pathological damage was mild or relatively severe, tonsillectomy may be beneficial to clinical remission or renal survival.

Conclusions

Tonsillectomy had a favorable effect on clinical remission and delayed renal deterioration in IgAN. In addition to patients with early stage IgAN, it may also be beneficial to IgAN patients with higher levels of proteinuria and relatively severe pathological damage.

Expansion of Escherichia-Shigella in Gut Is Associated with the Onset and Response to Immunosuppressive Therapy of IgA Nephropathy

BACKGROUND

Gut dysbiosis is postulated to participate in the pathogenesis of IgA nephropathy (IgAN). However, the key bacterial taxa closely associated with IgAN onset and treatment response have not been identified.

METHODS

We recruited 127 patients with IgAN who were treatment naive and 127 matched healthy controls (HCs) who were randomly divided into discovery and validation cohorts to investigate the characteristics of their gut microbiota and establish a bacterial diagnosis model for IgAN. A separate cohort of 56 patients and HCs was investigated to assess crossregional validation. A further 40 patients with primary membranous nephropathy (MN) were enrolled to probe disease-specific validation. A subgroup of 77 patients was prospectively followed to further dissect the association between alterations in gut microbiota and treatment response after 6 months of immunosuppressive therapy. Fecal microbiota samples were collected from all participants and analyzed using 16S ribosomal RNA sequencing.

RESULTS

Decreased α-diversity (Shannon, P=0.03), altered microbial composition (Adonis, P=0.0001), and a striking expansion of the taxonomic chain Proteobacteria-Gammaproteobacteria-Enterobacteriales-Enterobacteriaceae-Escherichia-Shigella (all P<0.001) were observed in patients with IgAN who were treatment naive, which reversed only in patients who achieved clinical remission after 6 months of immunosuppressive therapy. Importantly, seven operational taxa units, of which Escherichia-Shigella contributed the most, were determined to be the optimal bacterial classifier of IgAN (AUC=0.8635, 0.8551, 0.8026 in discovery, validation, and cross-regional validation sets, respectively), but did not effectively distinguish patients with IgAN versus those with MN (AUC=0.6183). Bacterial function prediction further verified enrichment of the shigellosis infection pathway in IgAN.

CONCLUSION

Gut dysbiosis, characterized by a striking expansion of genus Escherichia-Shigella, is a hallmark of patients with IgAN and may serve as a promising diagnostic biomarker and therapeutic target for IgAN. Further studies are warranted to investigate the potential contribution of Escherichia-Shigella in IgAN pathogenesis.

Clinical manifestations and pathological correlation of immunoglobulin A nephropathy in children

Background

IgA nephropathy in children has various clinical manifestations. Kidney biopsy is a gold standard for diagnosis by using Oxford classification 2016 with few studies about the correlation between clinical and pathology manifestations. This study aims to find these correlations at the time of diagnosis and during short-term follow-up.

Method

In this retrospective cohort study, 47 pediatric patients who underwent renal biopsy from 2010 to 2021 in Thailand, were included. Oxford classification 2016 has been used to score patients’ pathology. Univariate and multivariate associations have been used for correlation between clinical and pathologic parameters.

Results

The most common clinical manifestations were microscopic hematuria and proteinuria. There were 68% of children with mesangial hypercellularity (M1), 42% with segmental glomerulosclerosis (S1), 25% with moderate to severe crescent (C1/C2), 23% with endocapillary hypercellularity (E1), and 14% with moderate to a severe tubular atrophy/interstitial fibrosis (T1/T2). Microscopic hematuria was strongly associated with mesangial hypercellularity (M1) OR 7.14 (95%CI 1.83 – 27.88, p-value 0.005) and hypertension was strongly associated with segmental glomerulosclerosis (S1) adjusted OR 7.87 (95%CI 1.65 – 37.59, p-value 0.01). Intensive treatment was used more in the patients with tubular atrophy/interstitial fibrosis lesion on renal biopsy than other lesions from MEST-C scores OR 4.98 (95%CI 1.17–21.24, p-value 0.03). Furthermore, pulse methylprednisolone and cyclophosphamide were used in patients with crescentic lesions significantly than other lesions with OR 15.5 (95%CI 3.16- 75.93, p-value 0.001) and OR 5.75 (95%CI 1.31–25.29, p-value 0.021), respectively.

Conclusion

Tubular atrophy/interstitial fibrosis and crescent lesions were correlated to intensive treatment in short-term outcomes.

Time-Averaged Hematuria as a Prognostic Indicator of Renal Outcome in Patients with IgA Nephropathy

We aim to investigate the association of time-averaged hematuria (TA-hematuria) with the progression of IgA nephropathy (IgAN). Based on TA-hematuria during follow-up, 152 patients with IgAN were divided into a hematuria remission group (≤28 red blood cells [RBCs]/μL) and a persistent hematuria group (>28 RBCs/μL). The persistent hematuria group had a higher percentage of patients with macroscopic hematuria, lower levels of hemoglobin and TA-serum albumin, and more severe renal pathologic lesions. The composite endpoint is defined as a doubling of the baseline SCr level (D-SCr), or the presence of ESRD. During the mean follow-up of 58.08 ± 23.51 months, 15 patients (9.9%) reached the primary outcome of ESRD and 19 patients (12.5%) reached the combined renal endpoint. Kaplan-Meier analysis showed that the persistent hematuria group had a lower renal survival rate. The persistent hematuria patients who were incorporated with proteinuria (≥1.0 g/day) and low TA-serum albumin (<40 g/L) had the worst renal outcomes. Multivariate Cox regression indicated that TA-hematuria (hazard ratio [HR] = 0.004, 95% CI: 0.001, 0.008; p = 0.010) was independently associated with the progression of IgAN. Receiver operating characteristic analysis indicated the optimal TA-hematuria cutoff value for predicting the progression of IgAN was 201.21 RBCs/μL in females and 37.25 RBCs/μL in males.

IgA nephropathy with acute kidney disease: Characteristics, prognosis, and causes

BACKGROUND

The clinical manifestations and prognosis of IgA nephropathy (IgAN) are diverse. Some patients may present with kidney dysfunction lasting shorter than 3 months and meet the acute kidney disease (AKD) criteria. This study aimed to investigate the clinicopathological features, causes and prognosis of newly diagnosed cases of IgAN with AKD.

METHODS

1320 IgAN patients diagnosed via kidney biopsy between January 2012 and June 2018 were included in this retrospective study, with a median follow-up period of 35 months. We analyzed the clinicopathological, etiological variables, as well as short-term and long-term prognosis. The main outcome was a composite event of 40% decline in eGFR, kidney failure or death.

RESULTS

Incidence of AKD was 8.8% in the newly diagnosed IgAN patients, and was found to be an independent risk factor affecting the short-term (HR, 7.1; 95% CI, 2.3-22.2; P = 0.001) and long-term (HR, 1.8; 95% CI, 1.2-2.6; P = 0.006) prognosis, respectively. The most common cause of AKD was malignant hypertension-related AKD (MHT-AKD; 24.1%), followed by hematuria-related AKD (H-AKD; 12.9%), nephrotoxic-drug-exposure-related AKD (NTDE-AKD; 12.1%) and crescents-related AKD (C-AKD; 11.2%). The patients in AKD group had more severe clinicopathological characteristics and poor short-term and long-term prognosis than non-AKD group. In subgroup analysis, the MHT-AKD had the worst 5 years survival rate, followed by NTDE-AKD and C-AKD, whereas H-AKD had the best survival rate.

CONCLUSIONS

AKD is not rare among IgAN patients, and is an independent risk factor for short-term and long-term prognosis. IgAN patients with AKD resulting from different causes have different prognosis.

The Effectiveness and Safety of Abelmoschus manihot in Treating IgA Nephropathy: A Systematic Review and Meta-Analysis

Introduction

IgA nephropathy (IgAN) is a common issue. In China, Abelmoschus manihot (AM) is widely used in the treatment of IgAN. However, their combined effectiveness and safety for this purpose have not yet been explored. AM is an effective medicine for treating IgAN. This meta-analysis aimed to evaluate the effectiveness of AM for IgAN.

Materials and Methods

The Cochrane Library, PubMed, EMBASE, Allied and Complementary Medicine Database (AMED), Chinese Biomedical Literature Database (CBM), Chinese National Knowledge Infrastructure Database (CNKI), Chinese Science and Technique Journals Database (VIP), and the Wanfang Database were searched from their inceptions to June 2021. Random clinical trials (RCTs) comparing the effects of AM treatment in patients with IgAN were included. The study evaluated the efficacy or effectiveness of AM for IgAN and had clear outcome data, such as total effectiveness rate or proteinuria.

Results

A total of 11 RCTs with 850 participants were included in this meta-analysis. The results of the meta-analysis showed that, compared with that of the conventional therapy alone, being combined with conventional treatment was significantly more effective for the total efficacy rate (OR = 4.33; 95% CI = 2.66, 7.04; P < 0.00001) and proteinuria (MD = -0.41 g/24 h; 95% CI = -0.44, -0.38; P < 0.00001) but had no effect on serum creatinine (Scr) (MD = -2.23 μmol/L; 95% CI = -5.90, 1.45; P=0.24), eGFR (MD = -0.45 mL/min·1.73 m2; 95% CI = -1.24, 2.13; P=0.60), Bun (MD = -0.22 mmol/L; 95% CI = -0.59, 0.14; P=0.23), systolic blood pressure (MD = -0.04 mmHg; 95% CI = -2.59, 2.51; P=0.98), diastolic blood pressure (MD = -0.34 mmHg, 95% CI = -1.65, 2.33; P=0.74), systolic blood pressure (MD = -0.04 mmHg, 95% CI = -2.59, 2.51; P=0.98), or serum albumin (MD = 1.70 g/L, 95% CI = -1.06, 4.45; P=0.23).

Conclusions

AM provided additional benefits to proteinuria individuals with IgAN. However, due to the high clinical heterogeneity and small sample size of the included trials, future studies should conduct more rigorous RCTs on the clinical efficacy and safety of AM and RCTs with a larger sample size involving multicenters.

Lung cancer patients with nephropathy as the first manifestation: Literature review and clinical study report

Background

To investigate the relationship between membranous nephropathy (MN) and lung cancer.

Methods

To report patients with lung cancer detected by follow-up after the diagnosis of MN by renal biopsy in China-Japan Friendship Hospital from January 2010 to December 2019, and to study the prognosis of lung cancer-associated MN and have a review of the literature.

Results

Lung cancer was detected in six patients followed for 1–27 months (median 8 months) after the diagnosis of MN: including four cases of lung adenocarcinoma, one case of carcinoma in situ, and one case of small cell lung cancer with multiple metastases. Five cases were in remission after surgical resection, and one case was remitted after chemotherapy. Six patients were negative for serum anti-PLA2R antibodies, and glomerular IgG subclass deposition detected by immunofluorescence was positive for IgG1 and IgG2. Glomerular PLA2R, THSD7A, and NELL-1 stainings were assessed in all six patients; one patient was positive for glomerular PLA2R staining, two patients were positive for glomerular THSD7A staining, and all patients were negative for NELL-1 staining. A literature review of the relationship between MN and lung cancer was performed: seven articles about cancer-associated MN were searched, reporting 32 cases of MN associated with lung cancer, among which 14 cases had nephropathy as the first manifestation and only five patients had remission of MN after treatment of lung cancer.

Conclusions

A few lung cancer patients have nephropathy as the first clinical manifestation, and MN can also be remitted after treatment of lung cancer.

Spectrum of Biopsy-proven Native Kidney Disease in Central India

Spectrum of native renal biopsy reports varies geographically. Here, we tried to determine the prevalence of renal biopsy disorders and compare it with other studies. Retrospective study was performed at Saraswati Kidney Care Center, Nagpur and Jawaharlal Nehru Medical College, Sawangi, India. All the native kidney biopsies from January 2017 to March 2020 were included in the analysis. Demographic details of all the patients were recorded. Renal diseases were classified as glomerular, tubulo-interstitial, predominant vascular involvement and other disease categories. Total 347 native kidney biopsies were performed during the study period. Mean age of the patients at the time of biopsy was 41.41 ± 15.75 years. Majority of patients were males (58.5%). Most common indication for kidney biopsy was nephrotic syndrome (36.3%) followed by nephritic syndrome (19.9%). Among the glomerular diseases (GDs), 69% were primary glomerulopathies and 31% were secondary GDs. Immunoglobulin (IgA) nephropathy (30.85%) was the most common primary GD followed by membranous nephropathy (MN) (26.59%), focal segmental glomerulosclerosis (FSGS) (17.02 %) and minimal change disease (14.36 %). Among secondary glomerulopathies, lupus nephritis was the most common histopathological diagnosis (31.8%) followed by diabetic nephropathy (26.1%), amyloidosis (17%), infection related glomerulonephritis (11.3%), light chain deposition disease (4%) and anti-neutrophil cytoplasmic antibody associated vasculitis (3.4%). In tubulointerstitial disease, 33.3% had acute tubulointerstitial nephritis, whereas each 26.6% had acute tubular injury and cast nephropathy. The most prevalent diagnosis in our only study from central India was IgA nephropathy followed by MN and FSGS. Data analysis at regular intervals helps in understanding the changing trend of prevalence of native kidney disease and also gives understanding of geographical variations.

Metagenomics-based systematic analysis reveals that gut microbiota Gd-IgA1-associated enzymes may play a key role in IgA nephropathy

Background: IgA nephropathy (IgAN) is the most common type of glomerulonephritis in Asia. Its pathogenesis involves higher expression of galactose-deficient IgA1 (Gd-IgA1) and dysregulated intestinal mucosal immunity. The objective of this study was to explore whether specific gut microbiota and associated enzymes affect Gd-IgA1 in IgAN.

Methods: This study carried out shotgun metagenomic sequencing with Illumina on fecal samples collected from 20 IgAN patients (IgAN group) and 20 healthy controls (HCs group) who were recruited from January 2016 to December 2018 at the Second Clinical College of Guangzhou University of Chinese Medicine. Differences analysis in gut microbiota was performed to determine the overall microbiota composition, the representative enterotypes, and the microbiota abundance. Correlations between gut microbiota and clinical indicators were assessed by Spearman’s analysis. Moreover, the functional prediction of microbial communities and the quantitative calculation of enzymes encoded by microbiome were performed using the MetaCyc pathway and the bioBakery three platform, respectively.

Results:Bacteroides plebeius and Bacteroides vulgatus levels were higher, while Prevotella copri and Alistipes putredinis levels were lower in the IgAN group compared to HCs group. Enterotype I characterized by Bacteroides was closely related to the IgAN patients. Moreover, Bacteroides fragilis, Flavonifractor plautii and Ruminococcus gnavus were characteristic bacteria enriched in IgAN patients. Spearman’s correlation analysis found that Eggerthella lenta and Ruminococcus bromii were positively correlated with urine protein-creatinine ratio, while Ruminococcus gnavus showed a direct association with red blood cells in urine, and Bacteroides vulgatus and Ruminococcus gnavus were positively correlated with eGFR. These results indicated that intestinal dysbacteriosis occurred in IgAN patients and was associated with clinical and biochemical features. In addition, MetaCyc pathway analysis predicted microbiota-related metabolic pathways, including the biosynthesis of amino acids and glycans, were associated with the IgAN group. Microbial enzymes analysis highlighted that Gd-IgA1-associated α-galactosidase and α-N-acetyl-galactosaminidase secreted by Flavonifractor plautii were enriched in IgAN patients.

Conclusion: These findings suggested that α-galactosidase and α-N-acetyl-galactosaminidase secreted by Flavonifractor plautii might be related to the production of Gd-IgA1, indicating that enzymes originated from abnormal intestinal microbiota may contribute to the production of Gd-IgA1 and play an important role in the pathogenesis of IgAN.

Chemokine (C-C motif) receptor 2 is associated with the pathological grade and inflammatory response in IgAN children

Background

Chemokine (C–C motif) receptor 2 (CCR2) is involved in important physiological and pathological processes, such as inflammation and autoimmune diseases. Abnormal immune and inflammatory responses play a critical role in the development and progression of IgA nephritis (IgAN). However, the role of CCR2 in IgAN is unknown.

Methods

Fifteen IgAN children who were diagnosed by kidney biopsy provided kidney biopsy tissue, blood and urine samples, and age-matched healthy control subjects (blood donators n = 12; tissue donators n = 8) were included. Immunohistochemical analysis was used to detect the expression of CCR2, MCP-1, IL-6, IL-17, and TNF-α in the kidney tissues. Relative optical density (OD) was calculated by Image J software, and the correlation between CCR2 expression and pathological grade in IgAN children was analyzed.

Results

The expression of CCR2 significantly increased in mesangial cells of children with IgAN compared to that in control group (P < 0.001), especially in IgAN patients with Lee’s grade III to IV (P < 0.001). Interestingly, CCR2 expression was positively correlated with Lee’s grade (r = 0.9152, P = 0.0001) in IgAN children. The expression levels of inflammatory factors were markedly increased in IgAN children, and importantly CCR2 expression was positively correlated with it’s expression level.

Conclusions

The results suggest that CCR2 signaling might be involved in pathological process and inflammatory responses of children IgAN, and could potentially be an intervention target in children IgAN.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-022-02839-y.

Long-Term Kidney Prognosis and Pathological Characteristics of Late-Onset Lupus Nephritis

Background

Arguments still exist on prognosis of late-onset SLE, especially their kidney function. The purpose of this study was to investigate long-term kidney outcomes in patients with late-onset lupus nephritis (LN).

Methods

A retrospective long-term cohort study was conducted in adult Chinese patients with LN. The patients were divided into late- (>50 years) and early-onset (<50 years) LN groups. The baseline characteristics, especially the kidney pathological characteristics, were compared. The cohort was followed-up for kidney outcome defined as doubling of serum creatinine or ESRD. Cox regression analysis was used to examine the association between late onset LN and its outcomes.

Results

A total of 1,264 patients were recruited, who were assigned to late-onset LN with 102 patients and early-onset LN with 1,162 patients. The late-onset LN group showed a worse baseline kidney function and more chronic pathological lesions than the early-onset LN group. During a follow-up time of 55 (3, 207) months, 114 (13.1%) deaths occurred, 107 (12.2%) had doubling of creatinine, and 80 (9.1%) developed end-stage kidney disease. The 5- and 10-year survival rates of the late-onset LN group were 67.6 and 50.5%, respectively, which were much worse than those of the early-onset LN group (89.8 and 84.6%, respectively). However, no significant difference was found on kidney survival (log-rank chi-square = 3.55, p = 0.06). Cox regression analysis showed that late-onset LN was an independent risk factor for patient survival (hazard ratio = 3.03, 95% CI (1.39, 6.58), p = 0.005). Increased baseline serum creatinine was an independent risk factor for kidney survival of patients with late-onset LN.

Conclusions

Patients with late-onset LN had milder active lesions but severer chronic lesions in kidney pathology. They have poorer overall outcome but relatively favorable kidney outcome.

Trial Registration

ClinicalTrials.gov Identifier: NCT03001973, 22 December 2016 retrospectively registered.

Prediction of prognosis in immunoglobulin a nephropathy patients with focal crescent by machine learning

BACKGROUND AND OBJECTIVES

Immunoglobulin a nephropathy (IgAN) is the most common primary glomerular disease in the world, with different clinical manifestations, varying severity of pathological changes, common complications of crescent formation in different proportions, and great individual heterogeneous in clinical outcomes. Therefore, we aim to develop a machine learning (ML) based predictive model for predicting the prognosis of IgAN with focal crescent formation and without obvious chronic renal lesions (glomerulosclerosis <25%).

MATERIALS

We retrospectively reviewed biopsy-proven IgAN patients in our hospital and cooperative hospital from 2005 to 2017. The method of feature importance of random forest (RF) was applied to conduct feature exploration of feature variables to establish the characteristic variables that are closely related to the prognosis of focal crescent IgAN. Multiple ML algorithms were attempted to establish the prediction models. The area under the precision-recall curve (AUPRC) and the area under the receiver operating characteristic curve (AUROC) were applied to evaluate the predictive performance via three-fold cross validation (namely 2 training sets and 1 validation set).

RESULTS

RF was used to screen the important features, the top three of which were baseline estimated glomerular filtration rate (eGFR), serum creatine and triglyceride. Ten important features were selected as important predictors for modeling on the basis of data-driven and medical selection, predictors include: age, baseline eGFR, serum creatine, serum triglycerides, complement 3(C3), proteinuria, mean arterial pressure (MAP) and Hematuria, crescents proportion of glomeruli, Global crescent proportion of glomeruli. In a variety of ML algorithms, the support vector machine (SVM) algorithm displayed better predictive performance, with Precision of 0.77, Recall of 0.77, F1-score of 0.73, accuracy of 0.77, AUROC of 79.57%, and AUPRC of 76.5%.

CONCLUSIONS

The SVM model is potentially useful for predicting the prognosis of IgAN patients with focal crescent shape and without obvious chronic renal lesions.

IgA nephropathy treatment with traditional Chinese medicine: A case report

BACKGROUND

IgA nephropathy (IgAN) is a common primary glomerular disease that leads to end-stage renal disease with poor therapy efficacy. Traditional Chinese medicine (TCM) is effective in the treatment of IgAN and has the potential to become an alternative treatment for IgAN. Professor Yan-Qin Zou is a nephropathy expert, a National Chinese Medicine Master, and an heir to the Menghe School of Medicine.

CASE SUMMARY

A 28-year-old man had positive urinary protein and elevated serum creatinine (Scr) results and was diagnosed with IgAN 2-3 years prior to the outpatient department visit at our hospital in 2017. Professor Zou used the following methods to treat the patient: Invigorating the spleen and tonifying the kidney, removing dampness and clearing turbidity, quickening the blood and transforming stasis, and freeing vessels and regulating collaterals. She adjusted the prescription in accordance with the patient’s symptoms. After 6 mo of treatment, the symptoms had resolved and serological indexes were also decreased [Scr from 288.5 to 188.6 µmol/L, blood urea nitrogen (BUN) from 10.9 to 9.5 mmol/L, serum uric acid (UA) from 612 to 503 µmol/L]. During follow-up, BUN, Scr, and UA levels remained stable.

CONCLUSION

Professor Zou’s therapeutic strategy to treat IgAN using TCM was efficacious and a good reference for application.

Efficacy of Modified Huangqi Chifeng decoction in alleviating renal fibrosis in rats with IgA nephropathy by inhibiting the TGF-β1/Smad3 signaling pathway through exosome regulation

ETHNOPHARMACOLOGICAL RELEVANCE

IgA nephropathy is the most common form of primary glomerulonephritis and is a major cause of renal failure worldwide. Modified Huangqi Chifeng decoction (MHCD), a traditional Chinese herbal preparation, has clinical efficacy in reducing the 24-h urine protein levels in patients with IgA nephropathy. However, the molecular mechanism of MHCD needs further study.

AIM OF THE STUDY

This study aimed to investigate the mechanisms by which MHCD treatment alleviates renal fibrosis.

MATERIALS AND METHODS

An IgA nephropathy rat model was established using bovine serum albumin, carbon tetrachloride, and lipopolysaccharide. The rats were divided into control, model, telmisartan, low-dose MHCD, medium-dose MHCD, and high-dose MHCD groups. Treatments were administered to these groups for 8 weeks. Subsequently, the 24-h urine protein, serum creatinine, blood urea nitrogen, and blood albumin levels were measured. Pathological changes and degree of fibrosis in renal tissues were observed, and levels of the transforming growth factor-β1 (TGF-β1)/Smad3 signaling pathway components in renal tissues and TGF-β1 in urinary exosomes were measured.

RESULTS

Telmisartan and MHCD reduced 24-h urine protein levels, alleviated renal pathological injury, and decreased the renal expression of fibronectin, laminin, and collagen IV in rats with IgA nephropathy. Urinary exosomes were extracted and identified for further investigation of their role in renal fibrosis. MHCD reduced TGF-β1 expression in urinary exosomes and reduced TGF-β1 and p-Smad3 levels in renal tissues.

CONCLUSION

MHCD alleviated renal fibrosis in rats with IgA nephropathy by inhibiting the TGF-β1/Smad3 signaling pathway through the downregulation of TGF-β1 expression in exosomes.

Mesangial Cell-Derived Tenascin-C Contributes to Mesangial Cell Proliferation and Matrix Protein Production in IgA Nephropathy

AIM

Tenascin-C (TNC), a non-structural extracellular matrix glycoprotein, is transiently expressed during development or after injury, playing an important role in injury and repair process. The potential role of TNC in the pathogenesis of IgA nephropathy (IgAN) remains to be clarified.

METHODS

Immunohistochemistry staining for TNC was conducted on paraffin-embedded slices from renal biopsies of 107 IgAN patients, and correlation analysis was made between mesangial TNC expression and clinic-pathological parameters. In situ hybridization for TNC mRNA was further performed to figure out the cells that express TNC within glomeruli. In vitro experiments were also carried out on mouse mesangial cells (SV40 MES13) to elucidate the effect of TNC on mesangial cells.

RESULTS

TNC was expressed in the mesangial area of IgAN, as well as in fibrotic regions. Correlation analysis showed that higher mesangial TNC was associated with higher level of proteinuria, lower eGFR and more serious pathological lesions (MEST score). In situ hybridization revealed that abundant TNC mRNA expression was observed in the affected glomeruli of IgAN, but not in minimal change disease (MCD). Moreover, TNC mRNA co-localized with PDGFRβ mRNA, but not with PODXL mRNA, suggesting that TNC mRNA was expressed in the mesangial cells within glomeruli in IgAN. In vitro experiments showed that exogenous TNC promoted matrix protein production and mesangial cell proliferation, which was attenuated by an EGFR inhibitor.

CONCLUSION

Taken together, these results suggest that mesangial cell-derived TNC contributes to mesangial matrix expansion and mesangial cell proliferation, which is a potential therapeutic target in IgAN.

The pathogenesis of COVID-19-induced IgA nephropathy and IgA vasculitis: A systematic review

OBJECTIVE

IgA nephropathy (IgAN) and IgA vasculitis (IgAV) are part of a similar clinical spectrum. Both clinical conditions occur with the coronavirus disease 2019 (COVID-19). This review aims to recognize the novel association of IgAN and IgAV with COVID-19 and describe its underlying pathogenesis.

METHODS

We conducted a systematic literature search and data extraction from PubMed, Cochrane, ScienceDirect, and Google Scholar following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

Our search identified 13 cases reporting IgAV and IgAN associated with COVID-19 infection and 4 cases of IgAN following COVID-19 vaccination. The mean, mode, and median ages of patients were 23.8, 4, and 8 years, respectively. Most cases associated with COVID-19 infection were reported in males (77%). Rash and purpura (85%) were the most common clinical features, followed by gastrointestinal symptoms (62%). In symptomatic cases, skin or renal biopsy and immunofluorescence confirmed the diagnosis of IgAN or IgAV. Most patients were treated with steroids and reported recovery or improvement; however, death was reported in two patients.

CONCLUSION

There is a paucity of scientific evidence on the pathogenesis of the association of IgAN and IgAV with COVID-19, which thus needs further study. Current research suggests the role of IgA-mediated immune response, evidenced by early seroconversion to IgA in COVID-19 patients and the role of IgA in immune hyperactivation as the predominant mediator of the disease process. Clinicians, especially nephrologists and paediatricians, need to recognize this association, as this disease is usually self-limited and can lead to complete recovery if prompt diagnosis and treatment are provided.